If you’re a female athlete thinking about nutrition goals for the new year, here’s some good news: The science on fueling for performance is finally getting the attention it deserves. Below are four evidence-based strategies from Stanford experts. From prioritizing energy intake for bone health to incorporating fermented foods for gut health, these expert strategies aim to boost performance and overall well-being.
1. Some bones break first. Fuel enough to protect them
For female distance runners, stress fractures are a familiar problem. But here’s something that might change how you think about prevention: not all bones are equally at risk, and the ones most likely to break are the ones most sensitive to underfueling.
Bones like your pelvis and sacrum are rich in trabecular bone: spongy, metabolically active tissue that’s more sensitive to underfueling than denser cortical bone, which dominate in places like your shin. When you’re not eating enough, the trabecular bone weakens first. A missing period is another warning sign: underfueling disrupts hormones, which in turn affects bone health.
That’s the idea behind energy availability: you need enough fuel not just to perform, but to support everything happening behind the scenes, including bone health.
Michael Fredericson, professor of orthopedic surgery at Stanford University, and his colleagues spent seven years testing whether this insight could actually keep runners healthy. In the Healthy Runner Project, they tracked female collegiate runners at Stanford and UCLA, pairing them with dietitians who helped each athlete develop personal nutrition goals based on her training load and eating patterns. The focus was simple: eat sufficiently throughout the day with energy-dense foods, and get enough calcium and vitamin D.
The results, published in BMJ Open Sport & Exercise Medicine, were encouraging. Trabecular bone stress injuries (which correlate with a low energy state) dropped by nearly half. The message: eating enough and well is how you stay in the game.
2. Time your fuel to your body’s clock
Your body keeps time and expects you to eat by the clock. Within nearly every cell runs a 24-hour biological clock, governing when hormones rise and fall, when metabolism revs up or slows down, and when the body is primed to process fuel versus rest and repair.
Erratic eating patterns can throw that clock off. Researchers call it “eating jetlag“: when inconsistent mealtimes desynchronize your body’s internal rhythms. Your body digests food most efficiently when eaten within a consistent window of 10–12 hours. Eating late at night, when melatonin is rising, and your body expects rest, can compromise glucose regulation and fat metabolism.
Much of the research comes from mouse studies. Work by Satchin Panda, professor at the Salk Institute for Biological Studies, found that mice eating within a defined daily window stayed metabolically healthier than those eating at will, even when diet quality wasn’t perfect.
Human trials comparing specific meal-timing strategies are limited, but the evidence suggests three habits matter most: keeping your daily eating window under 12 hours, front-loading more calories earlier in the day, and avoiding food when melatonin levels are high late at night or very early in the morning.
3. Feed your gut microbiome
How much and when we eat matters, but so does what we eat: our food choices shape our microbial ecosystem. Erica Sonnenburg, Ph.D., senior research scientist of microbiology and immunology at Stanford University, studies how food choices influence the gut microbiome.
The Sonnenburg lab, in collaboration with Christopher Gardner’s group, designed a trial: 36 healthy adults were randomly assigned to follow one of two diets for 10 weeks. One group ate fermented foods (yogurt, kefir, kimchi, kombucha, and other fermented vegetables), while the other ate high-fiber foods (legumes, seeds, whole grains, nuts, and vegetables).
The results surprised even the researchers. Fermented foods offered a faster route to diversifying gut bacteria and reducing inflammation. Those eating fermented foods showed increased microbial diversity and decreased levels of 19 inflammatory proteins in their blood. Four types of immune cells showed less activation. The study, led by Hannah Wastyk and published in Cell, found a correlation: more fermented foods, more diversity.
The study focused on healthy adults, not athletes specifically, but the findings are suggestive. For athletes looking to manage inflammation, fermented foods may be worth adding to the plate.
4. Make fueling a team value
Nutrition education doesn’t work in a vacuum. In Fredericson’s Healthy Runner study, athletes at Stanford saw a drop in bone stress injuries while those at another institution did not. At the meeting, he offered a potential explanation: team culture.
At Stanford, coaching and dietitian staff remained stable throughout the seven-year study. Team captains became vocal advocates for the nutrition protocols. Athletes and coaches seemed genuinely committed, and the environment reinforced the message consistently.
At the other institution, staff turned over multiple times. Protocols had to be reintroduced each year, and athletes were slower to commit.
The takeaway: even the best nutritional guidance won’t stick without a culture that values fueling properly. For coaches, that means consistency and buy-in from leadership. For athletes, it might mean advocating for that support or finding teammates who reinforce good habits.
These insights were presented at the inaugural Female Athlete Research Meeting at Stanford, hosted by the Wu Tsai Human Performance Alliance. Topics included ACL injury prevention and the molecular science of performance, underscoring the importance of tailored nutrition strategies for female athletes.
Journal information:
BMJ Open Sport & Exercise Medicine
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